title: Evaluation of Streptomyces strains isolated from herbal vermicompost for their plant growth-promotion traits in rice.
abstract: Six actinomycetes, CAI-13, CAI-85, CAI-93, CAI-140, CAI-155 and KAI-180, isolated from six different herbal vermi-composts were characterized for in vitro plant growth-promoting (PGP) properties and further evaluated in the field for PGP activity in rice. Of the six actinomycetes, CAI-13, CAI-85, CAI-93, CAI-140 and CAI-155 produced siderophores; CAI-13, CAI-93, CAI-155 and KAI-180 produced chitinase; CAI-13, CAI-140, CAI-155 and KAI-180 produced lipase; CAI-13, CAI-93, CAI-155 and KAI-180 produced protease; and CAI-13, CAI-85, CAI-140 and CAI-155 produced ß-1-3-glucanase whereas all the six actinomycetes produced cellulase, hydrocyanic acid and indole acetic acid (IAA). The actinomycetes were able to grow in NaCl concentrations of up to 8%, at pH values between 7 and 11, temperatures between 20 and 40 °C and compatible with fungicide bavistin at field application levels. In the rice field, the actinomycetes significantly enhanced tiller numbers, panicle numbers, filled grain numbers and weight, stover yield, grain yield, total dry matter, root length, volume and dry weight over the un-inoculated control. In the rhizosphere, the actinomycetes also significantly enhanced total nitrogen, available phosphorous, % organic carbon, microbial biomass carbon and nitrogen and dehydrogenase activity over the un-inoculated control. Sequences of 16S rDNA gene of the actinomycetes matched with different Streptomyces species in BLAST analysis. Of the six actinomycetes, CAI-85 and CAI-93 were found superior over other actinomycetes in terms of PGP properties, root development and crop productivity. qRT-PCR analysis on selected plant growth promoting genes of actinomycetes revealed the up-regulation of IAA genes only in CAI-85 and CAI-93.
authors.affiliation: International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, Andhra Pradesh, India. Electronic address: s.gopalakrishnan@cgiar.org.
authors.forename: Subramaniam
authors.initials: S
authors.lastname: Gopalakrishnan
authors.forename: Srinivas
authors.initials: S
authors.lastname: Vadlamudi
authors.forename: Prakash
authors.initials: P
authors.lastname: Bandikinda
authors.forename: Arumugam
authors.initials: A
authors.lastname: Sathya
authors.forename: Rajendran
authors.initials: R
authors.lastname: Vijayabharathi
authors.forename: Om
authors.initials: O
authors.lastname: Rupela
authors.forename: Himabindu
authors.initials: H
authors.lastname: Kudapa
authors.forename: Krishnamohan
authors.initials: K
authors.lastname: Katta
authors.forename: Rajeev Kumar
authors.initials: RK
authors.lastname: Varshney
mesh_terms: D018533:Biomass; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D012275:Oryza / Q000254:growth & development* / Q000382:microbiology*; D063245:Plant Development / Q000187:drug effects*; D010937:Plant Growth Regulators / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000378:metabolism; D012988:Soil Microbiology; D013302:Streptomyces / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism / Q000502:physiology*; D013696:Temperature
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D010937:Plant Growth Regulators; D012336:RNA, Ribosomal, 16S; D012965:Sodium Chloride
keywords: Actinomycetes; Field evaluation; Plant growth-promotion; Rice; Streptomyces spp.